To meet the demand for wireless data traffic having increased since deployment of 4G (4th-Generation) communication systems, efforts have been made to develop an improved 5G (5th-Generation) or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a ‘Beyond 4G Network’ or a ‘Post LTE System’.
The 5G communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 60GHz bands, so as to accomplish higher data rates. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), Full Dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed in 5G communication systems.
In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud Radio Access Networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), reception-end interference cancellation and the like.
In the 5G system, Hybrid FSK and QAM Modulation (FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as an advanced access technology have been developed.
A handover refers to the change of a service evolved Node B (eNB) from which a User Equipment (UE) receives a current service into an eNB which can provide better service. For example, when service quality deteriorates while the UE receives the service from the serving eNB, the handover to a target eNB which can provide better service is made and the UE continuously receives the service from the target eNB.
FIGS. 1A and 1B illustrate examples of a heterogeneous network including a macro eNB and a small eNB according to the related art.
Referring to FIG. 1A, it is assumed that a heterogeneous network includes a plurality of cells, and each of the cells includes one macro eNB 105, 107, 109, and 111, and one or more small eNBs 113, 117, 119, 121, 123, 125, and 127. The small eNB may be, for example, a micro eNB, a pico eNB, or a femto eNB.
UEs 101 and 103 moving within an illustrated communication area 100 perform a handover to maintain the quality of service which the UEs receive.
When it is assumed that a serving eNB is the macro eNB 105, the UE may perform a handover from the macro eNB 105 to the macro eNB 107 or the small eNB 117 according to a movement position. When it is assumed that a serving eNB is the small eNB 117, the UE may perform a handover from the small eNB 117 to the small eNB 119 or the macro eNB 107 according to a movement position.
Referring to FIG. 1B, a graph illustrates a downlink received signal strength of the UE with respect to a distance between the macro eNB and the small eNB included in the heterogeneous network. Specifically, in FIG. 1B, a horizontal axis of the illustrated graph indicates a distance between the macro eNB 100 and the small eNB 120 and a vertical axis indicates a downlink received signal strength of the UE 130. That is, reference numeral 160 indicates a downlink received signal strength with respect to the macro eNB 110 and reference numeral 170 indicates a downlink received signal strength with respect to the small eNB 120. Further, reference numeral 140 indicates a macro eNB communication area in which data transmission/reception to/from the macro eNB 110 is possible, and reference numeral 150 indicates a small eNB communication area in which data transmission/reception to/from the small eNB 120 is possible.
As described above, in the heterogeneous network including the macro eNBs and the small eNBs, the UE may perform a handover from the macro eNB to the macro eNB, a handover from the macro eNB to the small eNB, a handover from the small eNB to the macro eNB, or a handover from the small eNB to the small eNB. For an efficient handover in the heterogeneous network, a method of adaptively applying a handover parameter according to types of a serving eNB and a target eNB is required.
However, at present no method has been prepared to adaptively apply the handover parameter according to the type of a serving eNB and a target eNB in the heterogeneous network.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.